1. Field of the Invention
This invention relates to new chlorinated 4-methylphthalic acids or anhydrides useful as intermediates for dyestuffs or pigments, and a process for preparating same.
2. Description of the Prior Art
As chlorinated derivatives of phthalic anhydride, there are known 3-chlorophthalic anhydride, 5-chlorophthalic anhydride, 3,6-dichlorophthalic anhydride, 3,4,5,6-tetrachlorophthalic anhydride and the like. 4-Methylphthalic acid or anhydride is also known. Chlorinated 4-methylphthalic acid or anhydride is, however, not hitherto known. Namely, neither of phthalic anhydride derivatives having one methyl group and one through three chlorine atoms on its benzene nucleus nor a process for the preparation of same has been known in the art.